Chemical insecticides are used to control insects that damage agricultural commodities such as tobacco, cotton, and soybeans. However, recent concerns about insecticide residues on commodities resistance of insects to chemical insecticides, hazardous exposure to pesticide applicators, environmental contamination, destruction of natural biocontrol agents and lack of newly developed insecticides have increased the need for alternative control methods. Furthermore, as pests become more resistant, more frequent treatments are required which increases a human health hazard. Alternative control methods must be found so as to minimize these health hazards.
An alternative to chemical insecticides is the use of biological control agents such as pathogens. To date, attempts at using pathogenic biocontrol agents have been directed primarily at using them in microbial insecticide formulations in a manner analogous to chemical insecticides. Some of the problems that have prohibited widespread use of biocontrol agents include formulation and delivery problems, inactivation by physical factors, higher costs from in-vivo production requirements, and reduced efficacy compared with chemical insecticides.
To be effective, biocontrol agents, like conventional pesticides must be critically timed, uniformly distributed, and available in appropriate dosage to the targeted host species. Unlike conventional pesticides, which are generally toxic, many biocontrol agents are host specific or attack a narrow range of hosts. Furthermore, with the declining arsenal of chemical pesticides due to government regulation and the renewed interest in air and ground water quality, there is a need for effective biocontrol agents as well as a means for disseminating the agent. Biocontrol agents can be conveyed into the agroecosystem by a variety of non-conventional methods including autodissemination (Gard and Falcon, In Microbial control of insect pests: Future strategies in pest management systems, pp. 46-54, 1978; Ali et al., Entomophaga 32: 387-398, 1987; Elmore et al., J. of Insect Path. v. 6, 430-438, 1964; Ham et al., J. Invertebr. Path. v. 24, 70-81, 1974), predators (Abbas, Z. Pflanzenkenkr Pflangenschutz 95: 606-610, 1988; Young et al., J. Entomol. Sci., v. 20, 212-218, 1985; King et al., J. Entomol. Sci. v. 23, 394-398, 1988), parasites (Young et al., J. Entomol. Sci. v. 24, 500-506, 1989a; Young et al., Environ. Entomol, v. 19, 251-256, 1989b; Brown et al., Southwest. Entomol., v. 14, 139-146, 1989), insectivorous birds (Vyas et al., Indian J. Agric. Sci. v. 58, 661-663, 1988), honeybees (Childress et al. , Phytopathology, v. 77, 167-172, 1987), blown dust (Oloffsson, Entomol. Exp. Appl. v. 46, 181-186, 1988), and others. With autodissemination, a biocontrol agent composition can be delivered to eggs of an insect so that it is readily available to the most susceptible life stage, the neonates. Thus, much smaller quantities of the formulations are used compared with the amounts required for inundative sprays. An autodissemination technique also can be used to augment insect control programs, thus decreasing the amount of chemical insecticide used.
There are various types of prior art devices for destroying insects using insecticides and/or pheromones.
For instance, U.S. Pat. No. 4,671,010 ('010) discloses a tubular housing filled with a sex-attracting pheromone where the exterior surface of the tube is coated with an insecticide. Another device is disclosed in U.S. Pat. No. 5,042,194 where the trap chambers are coated with a contact poison. One disadvantage of these devices is that they use an insecticide which kills or incapacitates the insect that comes in contact with it. Therefore the insecticide is not disseminated to the larval population which is responsible for the majority of crop damages.
U.S. Pat. No. 4,485,582 discloses an insect feeding station wherein insects enter the station from the side or from below through an opening 34 in an extension 32. The station contains a bait which is a mixture of poison and food material to attract the insects. The insects eat the poison and then exit the station to die elsewhere. However, this has the similar disadvantage in that the insecticide is not disseminated to the larval population.
The present invention provides a safe, simple, cost effective alternative strategy for conveying biocontrol agents to specific targeted sites which is different than the insecticide containing prior art insect traps.